Radiation therapy has been the preferred method for treating many kinds of cancer in different parts of the body. In fact, half of all people afflicted with cancer are treated with radiation, and the number of cancer patients who have been cured is rising every day. For many patients, radiation is the only kind of treatment needed. In fact, a large number of people are free of cancer after having radiation treatments alone or in combination with surgery, chemotherapy, or biological therapy.
Doctors can also use radiation before surgery to shrink certain types of tumors. After surgery, radiation therapy may be used to stop the growth of any cancer cells that remain. Even when curing the cancer is not possible, radiation therapy still can bring relief. Many patients find the quality of their lives improved when radiation therapy is used to shrink tumors and reduce pressure, bleeding, pain, or other symptoms of cancer.
Radiation therapy can be in either of two forms: external or internal. Some patients receive both forms of therapy, typically one after the other. Most people who receive radiation therapy for cancer are treated with the external type of radiation therapy which is usually given during outpatient visits to a hospital or treatment center. In external therapy, a machine directs high-energy rays or particles at the cancer and the normal tissue surrounding it. One type of machine that is used for radiation therapy is called a linear accelerator. High-energy rays may also come from a machine that contains radioactive substance such as cobalt-60. The various machines used for external radiation work in slightly different ways and some are better for treating cancers near the skin surface while others work best on cancers deeper in the body.
However, like many other treatments for disease, there are risks for patients who are receiving radiation therapy. The brief high doses of radiation that damage or destroy cancer cells also can affect normal cells. When this happens, the patient has side effects which can be manifested in the form of headaches, loss of appetite, loss of hair, lethargy, etc. In fact, high doses of radiation can actually kill cells or keep them from growing and dividing. Furthermore, the function of organs near a cancer can be impaired by the radiation. This risk often limits the utility of radiation therapy. Ideally, radiation could be delivered to the area or organ of interest with little or no exposure to normal adjacent tissues.
The conventional method of protecting healthy areas or cells from exposure to the radiation treatment involves the use of external blocking shields or pads which are used to cover certain parts of the body to protect normal tissues and organs. Unfortunately, due to the basic overlapping nature of tissues and organs within the human body, these prior art devices for preventing irradiation of normal tissues are limited in their effectiveness. Furthermore, it is often difficult to concentrate the radiation in an easily definable area. As a result, areas surrounding the site to be irradiated are more often than not exposed to the radiation.
Thereby it would be desirable to have a device for more effectively and predictably controlling the exposure of the human body parts to radiation during radiation therapy. Such a device would either shield the tissues to be protected from radiation or displace them from the tissues to be irradiated such that a highly effective dose of energy could be delivered to the malignancy and little or none delivered to the surrounding or adjacent tissues or organs.